Nov 18, 2019
Several methods of extracting rosemary
1. Steam distillation
Extracted material: volatile ingredients of rosemary
Principle: According to the vapor pressure of each component of volatile oil, the essential oil is extracted from the raw material by steam.
Influencing factors: pulverization degree, soaking time, water addition amount, extraction time
Advantages: simple operation, low cost, and can reduce the distillation temperature of the perfume component, prevent the decomposition or deterioration of the extract, the extraction process is mature, the output is large, and the environment is not polluted.
Insufficient: The steam distillation method has a long extraction process and the system is open. The process will cause heat instability and loss of oxidizable components, and it has a destructive effect on some components, so it is only suitable for extracting essential oils. If other active ingredients need to be extracted, other extraction methods need to be combined, and the process will become complicated and costly.
2. Solvent extraction method
Extracted substances: effective substances in rosemary
Principle: An organic solvent such as petroleum ether, n-hexane, ethyl acetate, acetone or ethanol is used as an extraction solvent to dissolve the effective substance.
Considering safety, efficiency, and economic factors, rosemary extraction generally uses ethanol as an organic solvent, and ethanol is suitable for extraction within 2 hours, and the liquid to material ratio is 10:1. The concentration of ethanol should not be too large to avoid the dissolution of non-polar substances in rosemary, such as chlorophyll. Moreover, the method is often combined with methods such as microwave oscillation to achieve higher yields.
Influencing factors: ethanol concentration, extraction temperature, ratio of material to liquid, extraction time and number of extractions.
Advantages: The extraction of medicinal materials rich in carnosic acid is analyzed by a solvent method, and the extraction process has high extraction rate and good stability, and is suitable for industrial application; The extraction of ursolic acid from rosemary has a yield of 92.38%, and its purity is high. At the same time, various antioxidants in rosemary can be extracted. The method is safe, effective, environmentally friendly, easy to operate, and relatively low in cost.
Insufficient: Carnosic acid is greatly affected by the operating conditions during the separation process, and is easily converted into the oxidized intermediate product carnosol, which reduces the antioxidant effect, which makes it difficult to meet the requirements of the international market.